This invention concerns a mounting arrangement for a supplementary crop processing device for a harvester and more particularly, a mounting for a bulky, heavy device which is movable selectively between operating and non-operating positions, such as a straw chopper on a combine harvester.
In a typical combine harvester, either so-called conventional or rotary, straw from the separator is discharged downwardly from the hood structure at the rear of the combine. This straw is already somewhat reduced from the threshing and separating operations and, if it is desired to reduce it further, it is passed through a straw chopper.
The most common type of straw chopper consists of a transversely mounted flail rotor associated with a transverse array of fixed shear blades carried in a housing with an upwardly directed inlet opening and supported beneath the combine hood to intercept the flow of straw from the separator. In some harvesting conditions, or to preserve longer straw for some later use, it is desirable to return the straw to the ground without passing it through the straw chopper.
Two principal methods are known for removing the chopper from the path of the straw. U.S. Pat. No. 3,712,309 (Schmitz) discloses a chopper supported on a pair of approximately horizontal rails, one on each side of the combine hood. The straw chopper may be releasably secured in either a rearward operating position or in a forward transport (or inoperative position) in which the straw chopper is removed from the path of the straw flow from the separator. In a second method, embodied, for example, in the German-made John Deere combines model numbers 1065 and 1075, the straw chopper is supported on a linkage permitting it to be pivotably swung from a rearwardly operating position to a forward transport position. In a third approach, Scott (U.S. Pat. No. 4,526,180) inactivates the straw chopper for discharging the straw into a windrow by opening a door in the floor of the chopper casing, allowing the straw to be discharged before reaching the straw chopping rotor. The straw chopper unit, as a whole, remains fixed in relation to the combine hood.
These known methods of inactivating the straw chopper each have their disadvantages and limitations. In the simple slide arrangement of Schmitz, even if the slide could be maintained horizontal (which, with reference to the overall combine design, is generally not convenient), moving the chopper is difficult. Manually moving the chopper or man-handling it along the slides is made difficult by a combination of high frictional forces between the chopper and mating slide members and, if the chopper is not kept perfectly square with the combine, binding or jamming occurs. Given the widths of many modern combines and hence, the relatively large lateral spacing between the support rails of the chopper and the length of the chopper structure engagement with the rails, it is often difficult even for two men to move one of the larger choppers. Introduction of anti-friction devices (rollers or the like) at the sliding surfaces have been proposed, but these would not necessarily overcome the binding or cocking problem, would add to the cost of the chopper, and in some conditions, increase the hazards to the operator in moving the chopper by making it difficult to control on a slope, etc. (unless very sophisticated anti-friction devices were used, giving support and guidance in both horizontal and vertical planes).
The John Deere swinging linkage arrangement potentially costs more to manufacture than a simple slide (as in Schmitz) even if only a simple linkage is used. Use of a simple linkage limits the range of chopper position and attitude in the transport position. The swinging chopper approach requires relatively more sophisticated fastener or latching arrangements for securing the chopper in its two positions, contributing significantly to the potential increase in manufacturing costs compared with the simple slide arrangement.
The apparently simple convertibility of Scott is appealing, requiring only the raising or lowering of the lower front side portion or pan of the casing (58) allowing straw to be dumped straight through the straw chopper casing (15) and onto the ground without being chopped. However, the advantage of maintaining the straw chopper rotor in a fixed position relative to the straw discharge from the combine separator must require some tradeoff in terms of cost of sheet metal deflectors, space consumption, and optimization of feeding the chopper rotor if the rotor is to be effective both in and out of the flow material from the combine separator.